The statements in this section merely provide background information related to the present disclosure and do not constitute prior art.
Recently, a user terminal such as mobile phones, smart phones, or etc. has become necessities in human life and is used by people regardless of age or gender. Service providers and terminal manufacturers make effort to be prominent from other competitors.
The user terminal has been developed as a multimedia device providing several functions of saving a phone book, playing a game, texting, sending and receiving an e-mail, ringing a morning call, playing MP3 (MPEG Audio Layer 3), a digital camera and using a wireless Internet service to a user.
Meanwhile, since the texting function among the above functions of the user terminal is relatively cheaper than a voice call, many users are using the texting function.
The message, for example, is SMS (Short Messaging Service), MMS (Multimedia Messaging Service), and a packet-based message. The SMS refers to a message service by which a simple text message is transmissible, and the MMS refers to a message service by which a message including a video file, a picture file, a music file, and the simple text is sendable. In addition, the packet-based message is a message to be transmitted through a packet based network. Users have a conversation with text message parsed and transmitted in a type of the packet-based message. A video file, a picture file, or a music file like MMS are also allowed to be transmitted in the type of the packet-based message.
However, the inventor(s) has noted that recently a number of companies or unspecific people are making use of the above functions such as SMS/MMS message function, etc. for advertisements of them; thus, a user becomes uncomfortable due to the reception of many unnecessary messages. In addition, the inventor(s) has noted that spam messages such as a gambling advertisement message or an obscene message etc. from abnormal companies are also problematic.
Further, the inventor(s) has noted that there is a spam (smishing) message in which a malicious URL is inserted, among messages such as SMS messages, MMS messages or packet-based messages, etc. that have been transmitted to the user terminal for a purpose of an announcement, an advertisement or an advertisement of a company, an advertising person, etc.
The inventor(s) has experienced that in this case, when the user clicks it, the spam message including the malicious URL causes to the user a damage that an application including a malicious code is installed in a user terminal or the user accesses a web site of smishing enterprise located abroad. Accordingly, the inventor(s) has noted that such a potential danger to be caused by a malicious URL is required to be prevented. The inventor(s) has noted that for example, the damage might be prevented by blocking a transmission of a message including the malicious URL among the messages being transmitted to a user terminal or by alerting a risk of the malicious URL to the user terminal when the message is transmitted to the user terminal.
Meanwhile, the inventor(s) has noted that as a known method to prevent damage caused by the above malicious URL, there has been provided a spam filtering system or SMSC (short message service center) filtering an abnormal message causing a malicious application to be installed by detecting the abnormal message based on pattern-searching in the message. However, the inventor(s) has experienced that the number of patterns to be detected by the pattern-searching is highly limited, and therefore, the filtering performance is not enough to filter out many kinds of malicious URLs, since patterns registered as malicious are obtainable by receiving a report regarding the malicious URL from a user and analyzing it.
In addition, the inventor(s) has noted that another method has been suggested by a security software provider. The inventor(s) has noted that according to the another method, it leaks personal information through several testing terminals, and then collects all messages trying to propagate malicious application and obtain full descriptions of the messages. However, the inventor(s) has noted that since a hundred of variant malicious applications that aim to obtain personal information of the user are found for a week and a number of obtainable malicious applications are limited, the performance of the another method also is not sufficient.